q5 - super6818

[ArchivalUser]

A couple wish to know their risk of having a child with an autosomal recessive disorder. The man's brother is affected with the disorder, whereas his wife has no family history of the condition. The carrier frequency in the general population is estimated to be 1 in 100. The risk that they would have an affected child is:
A 1/4
B 1/400
C 1/600
D 1/800
E 1/1200

[ArchivalUser]

I'm getting .0066 so clearly I'm not doing it right. Anyone able to break it down?

[ArchivalUser]

b.

[ArchivalUser]

cc

[ArchivalUser]

answer should be ee

[ArchivalUser]

can someone plzzz explain this one ???

[ArchivalUser]

is it b ?? .. can someone with help me with this one ?

[ArchivalUser]

C.
chance the man has a mutant allele is 2/3. chance he will pass it on is 1/2
chance the child will get this mutant allele is 2/3 * 1/2 = 1/3

chance the mother has this mutant allele is 1/100. chance she will pass it on is 1/2.
chance the child will get this mutant allele is 1/100 * 1/2 = 1/200

and then you do 1/3 * 1/200 = 1/600

[ArchivalUser]

carrier frequency 2pq=1/100 so,q=1/200 ,so chance of maternal being carrier q=1/200,chance to pass a allele 1/2.in father side 2/3*1/2=1/3 ,so total probability=1/200*1/3*1/2=1/1200

[ArchivalUser]

how do u know that the father is 2/3 chance of mutant allele?